Occurrence of Lernaea cyprinacea on Arkansas River Shiners and Peppered Chubs in the Canadian River, New Mexico and Texas

Abstract

Parasitic cyclopoid copepods of the genus Lernaea commonly parasitize freshwater fishes. Infestations have been reported from Africa, Asia, Europe, and North America (Hoffman, 1999), and most reports have involved the cosmopolitan species Lernaea cyprinacea (Marcogliese, 1991). All naupliar and the first 4 copepodid stages follow the general developmental pattern for cyclopoid copepods (Grabda, 1963). Mating between males and females takes place during the fifth copepodid stage, and then females attach to the skin and gills of fish where they continue to develop. At maturity, female Lernaea have an unsegmented body, are several millimeters in length, and attach to the host fish by a basal cephalic anchor, from which their common name, anchor worm, is derived. Although substantial mortality of fishes due to Lernaea parasitism is most closely associated with fish culture and aquaria-propagated populations (Dempster et al., 1988), a number of studies have reported the prevalence and effects of Lernaea parasitism in stream fish populations (Amin et al., 1973; Whitaker and Schlueter, 1975; Bulow et al., 1979; Adams, 1984; Medeiros and Maltchik, 1999). Prevalence of Lernaea parasitism on stream fish populations typically is less than 20% during the summer (Wilson et al., 1966; Bulow et al., 1979; Robinson et al., 1998); however, during periods of extreme environmental conditions, prevalence can exceed 60% (Medeiros and Maltchik, 1999). Members of the family Cyprinidae are among those fishes most susceptible to Lernaea infestation (Shariff et al., 1986; Goodwin, 1999). In the Arkansas River drainage, 2 cyprinids, the Arkansas River shiner, Notropis girardi, and peppered chub, Macrhybopsis tetranema, have been extripated from 85% and 90%, respectively, of their historic ranges (Larson, 1991; Luttrell et al., 1999); however, both species remain common in the Canadian River upstream from Lake Meredith, Texas (Bonner and Wilde, 2000). The purpose of this study was to determine the prevalence and potential effects of L. cyprinacea parasitism on Arkansas River shiners and peppered chubs in the Canadian River, New Mexico and Texas. Arkansas River shiners and peppered chubs were collected during September 1996 through August 1998 at 3 locations on the Canadian River, New Mexico and Texas, between Ute Reservoir (Quay Co., New Mexico) and Lake Meredith (Potter, Moore, and Hutchinson counties, Texas). Fish were sampled monthly except during May through August, when sampling was conducted twice per month. Fish were collected with a 1.8 X 3.4-m